Telephone-switch



(No Model.)

H. W. COMSTOCK.

TELEPHONE SWITCH.

Patented June 9, 1885.

i Arena* Fries@ HENRY WV. COMSTOCK, OF RED OAK, IOWA.

TELEPHONE-SWITCH.

SPECEFICATION forming part of Letters Patent No. 319,789, dated June 9, 1885.

` Application filed February 1G, 1885. (No model.)

To @ZZ whom it may concern:

Be it known that I, HENRY W. CoMsTocK,

of Red Oak, in the county of Montgomery and State of Iowa, have invented certain new and useful Improvements in Telephone-Switches; and I do hereby declare the following to be a full, clear, and exact description lof the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to telephone-switches of that class in which a moving telephone-supporting arm or plate operates to make and break circuit, the arm being held in one position by the weight of the telephone and shifting automatically to another position when the telephone is taken off. The arm or plate usually opens the transmitter-battery circuit, and closes the signal-bell circuit when weighted down by the telephone, and closes the batterycircuit for use when relieved of the weight, the opening being caused by the removal of contacts or springs one from another, or the removal of the arm or plate from contacts or springs.

One of the chief sources of trouble in keepl ing a telephone apparatus in good working order lies in the fact that the contacts soon become dirty, and the currents are therefore obstructed. This comes from the fact that when the circuits are opened the contacts are left uncovered,so that they become foul with dust, and are also rusted by exposure to the air.

It is the object of my improvement to keep bright and fresh all the circuit-closing contacts, so that the currents will ilow freely whenever the circuits are closed for the purpose of using the apparatus; and with this end in view it consists in certain novel constructions and combinations, whereby the telephone-supporting arm or plate is caused to cover and protect the contacts while the circuits are opened, and to wipe off and brighten said contacts each time said arm or plate moves for closing circuit.

The improvement will be fully understood from the following particular description, in connection with the accompanying drawings, in which- Figure lis a perspective view of a sufficient portion of the casing of a telephone apparatus for illustration of my invention, such parts being omitted as not concerned in the improvement. Fig. 2 is a detached view of two circuit-springs in position to close circuit, the telephone-supporting arm being shown in section. Fig.`8 is a similar view of the springs separated by the arm, which is forced in between them.

The letter A indicates the inclosing casing, the front of which is open in order to show the interior part.

B is a telephone-supporting arm, pivoted at b within the casing, and extending through a `slot, c, in the wall opposite its pivoted end,

the outer end of the arm having a fork, B', to receive the telephone T. A spring, d, raises the arm when it is not supporting the telephone; but when the telephone is in the fork the arm will be depressed to the bottom of the slot c.

On the bottom of the casing stand, in the present instance, two pairs of contact-springs, E E and F F. The springs of each pair, respectively, press againsteach other at their tops, their tips being bent away in opposite directions from the point of Contact.

The telephone-sup porting arm is so arranged that when depressed it enters between the springs of each pair and forces them apart. That portion of the arm which enters between the springs is covered by a non-conducting material, as at I, so that the springs will be electrically insulated from each other by the interposition of said portion of the arm.D In the present instance the arm is made thin at the part which enters between the springs, and is there covered, preferably, by afolded strip of Ane emery cloth or paper, t', which is held in 'position by a plate, j, which binds its margins on the top of the arm. It will be seen that when the arin is depressed and the springs forced apart the contact Surfaces of said springs will be covered and protected from dust and the corrosive action of the air by the material with which the interposed portion of the arm is covered, and as the arm moves up and down the emery-cloth will have aslightly abrasive action, sufficient to clean the contlC- surfaces of the springs, removing therefrom all rust, and keeping such surfaces bright and in efficient condi-tion for forming electric contact between the two springs when they are allowed to come together.

IOO

I In the present instance the springs E and E are supposed to be included in the transmitter-battery circuit and the springs FFin the line-wire or hand-telephone circuit; or these 0r additional springs may be used as part of any circuit to be opened and closed by the sup'- porting-arm.

-While it is preferable it is not essential that the supporting-arm shall have its spring-separating portion covered with abrasive material, as any non'conducting material would rub and keep clean the springs, while also serving to insulate 'them from each other. Silk or any other non-conducting fabric might be used to cover the arm instead of the emerycloth; or the arm might have non-conducting shields of .hard rubber, wood, or other rigid material; or a section of non-conducting material might be inserted in the arm, the effect being in all the cases mentioned that the contact-surfaces of the springs are covered and protected when separated, and rub and thereby cleaned each time the telephone-supporting arm is operated for either breaking or closing the circuits.

I do not of course limit myself to any particular form or arrangement of the arm or springs, and at the same time I may suggest that switching devices involving the essential features of my invention may be used for other purposes than telephone-switches.

Having now described my invention and explained the operation thereof, I claiml. The combination, with two pair of metallic contacts held normally together by springpressure, of a non-conducting arm or plate arranged to enter between the contacts of each pair4 and have a sliding action against the entire engaging surfaces of said contacts, substantially as set forth..

2. The combination, with two metallic springs arranged in a circuit and pressing normally against each other to complete the circuit, of an arnrplate having non-conducting abrasive surfaces, and arranged to move in between said springs for separating them, and to be withdrawn therefrom for closing circuit? substantially as described.

3. In a telephone-switch, the combination, with the metallic springs pressing 'normally against each other, of the telephone-supporting arm having a portion provided with insu lating-surfaces, and arranged to swing in between said springs when depressed by the weight of the telephone, and a spring for retracting said arm from the circuit-springs when the telephone is removed.

4f. The combination, with the springs E E',

pressing normally against each other and forming part of the circuit, of the hinged telephone-supporting arm having abrasive nonconducting surfaces arranged to enter between and separate said springs and to clean thc same, substantially as described.

In testimony whereof I have signed this specification in the presence 0f two subscribing witnesses.

HENRY W. COMSTOCK.

Witnesses:

H. E. DEEMER, ETHEL MURPHY. 

